In recent years, as an interface for multimedia data transfer, IEEE (The Institute of Electronical and Electrical Engineers) 1394, High Performance Serial Bus, for realizing a high speed data transfer and a real-time transfer has been standardized.
According to the IEEE1394 standard, for example, a plurality (up to 63) of application side circuits such as MPEG (Moving Picture Expert Group) transporters or the like can be connected to the IEEE1394 serial bus. A connecting format of the IEEE1394 serial bus has been specified so as to have a node branch, namely, what is called a tree shape. A circuit serving as a branch point, namely, a node of the tree-shaped connecting format is a physical layer circuit in each IEEE1394 serial interface.
According to the IEEE1394 standard, the insertion or ejection of a bus cable to/from a port can be performed in a hot state, namely, in a state where a power source is turned on and an apparatus is operating. A bus reset is generated at a point when the node is added or deleted by the insertion or ejection of the bus cable to/from the port and a parent/child relation between the nodes is determined.
In the case where the cable is connected in a loop shape such as a case where the user erroneously connects or the like, the parent/child relation cannot be determined and the data cannot be transferred.
It will be, therefore, convenience if there is a function such that in the case where the cable is connected in a loop shape, the user is notified of such a fact through a display unit of each electronic apparatus as an application side circuit. However, an electronic apparatus having such a function does not exist yet.